The present invention is used for sampling airborne particles (aerosols) and for health hazard evaluation of airborne particles.
For the evaluation of the health hazard from airborne particles, various organizations and agencies recommend or require that particle sampling conform to particle size-selective criteria. Those criteria are based on estimates of the probabilities that particles will penetrate to specific regions of the respiratory system. For example, the American Conference of Industrial Hygienists (ACGIH) has defined sampling criteria for the inhalable particulate mass for particles entering the nose or mouth and penetrating to any region of the respiratory tract, the thoracic particulate mass for particles penetrating into the tracheobronchial and gas-exchange regions and the respirable particulate mass for particles penetrating into the gas-exchange region. Those criteria prescribe the percent collection vs. particle aerodynamic diameter. Other sampling criteria include that of the U.S. Environmental Protection Agency (USEPA) for sampling in ambient air, called PM10. The British Medical Research Council (BMRC) has established criteria for sampling pneumoconious-producing dusts.
Various sampling devices are used to approximate the various sampling criteria. A 10 mm Nylon cyclone is used for the ACGIH respirable fraction. A disadvantage of cyclones is that the sampling characteristics are relatively fixed and must be determined empirically. The BMRC criteria is based on a horizontal elutriator. Penetration characteristics of an elutriator can be predicted from theory. However, the horizontal elutriator is not practical for personal sampling. Therefore, in coal mines, the 10 mm cyclone is used, and a correction factor is applied to approximate the BMRC criterion. Various inlets have been empirically designed to satisfy the USEPA PM10 criteria, which does not conform to the characteristics of any standard type of sampler.
A multiplicity of sampling criteria exist. The criteria continue to change as organizations reconsider the problem to take into account advances in knowledge.
A need exists for a particle sampler which is capable of accurately sampling according to a preselected sampling criteria.